A 55-year-old homeless man has been charged after he allegedly struck a 79-year-old woman on the head with a blunt metal object in an alleged unprovoked attack in downtown Honolulu.

Suspect Donald M. Foafoa was charged Saturday with first-degree assault via felony information. He is being held in lieu of $50,000 bail.

First-degree assault is a class B felony that’s punishable by up to 10 years in prison if convicted.

Honolulu police said the woman was sitting at a bus stop waiting for the bus to arrive in the area of Bishop and Merchant streets when a man struck the victim’s head with a metal object at about 8:45 a.m. Friday. She was taken in serious condition to hospital.

The suspect and victim are not known to one another.

Police said the suspect, identified as Foafoa, fled but later returned to the scene where officers arrested him on suspicion of assault.